A new map of MPs’ constituencies produced by the boundary commissions for England, Scotland and Wales would boost the Conservative party’s chances of winning an election and do away with Jeremy Corbyn’s north London constituency seat.

A Labour party plan that would save Jeremy Corbyn’s seat, which is threatened by boundary changes, has resulted in a furious reaction from one of the leader’s closest allies whose own constituency is to be split into three under the proposals.

Labour has called for the government to halt its shakeup of parliamentary constituencies, arguing that the rush of new voters before the EU referendum means the proposed changes will be out of date and “an affront to democracy”.

Two hundred Labour seats – more than 85% of the party’s total – could be affected by the review of parliamentary boundaries due next month, according to a detailed analysis of the review’s likely impact.

Labour may need a swing in England larger than it managed in 1997 to win a bare overall majority at the next election, with its challenge made steeper because of the government’s boundary changes, according to a new analysis.

Labour will face “huge challenges” to win the 2020 general election as changes to parliamentary boundaries and Britain’s ageing population move against the party, the former foreign secretary Margaret Beckett has warned.

A new map of MPs’ constituencies produced by the boundary commissions for England, Scotland and Wales would boost the Conservative party’s chances of winning an election and do away with Jeremy Corbyn’s north London constituency seat.

A Labour party plan that would save Jeremy Corbyn’s seat, which is threatened by boundary changes, has resulted in a furious reaction from one of the leader’s closest allies whose own constituency is to be split into three under the proposals.